5G WiFi

802.11ac is a waste of money currently. NO device meets the standard...because there is no standard for another year. You take huge risk of incompatibility.
Besides none of your end devices will support it.

Even with 802.11n all your devices would have multiple antenna in them and support mimo to get above 150m.

+1, too early -- just use dual band N, which is still overkill for many devices that are G or 2.4GHz N. N routers have really dropped in price now that a few very early 802.11ac products are out there.

Hi all. Thanks for the replies.

I'me looking for the a/c routers because they are really recent, and maybe they are more future proof. I don't have any device supporting a/c at the moment, but I can in a year or so, and I could buy an adapter for the iMac.
They are backward compatible with draft N.
ASUS is already launching some motherboards and laptops supporting a/c.

What I need is a very good wireless router, from wich I could get a stable and fast connection, and the best range possible. I want to disable the wireless from my ISP Provider router, and connect a "real" wireless router.

From what I've seen the best dual band N routers cost the same as the a/c routers.

What do you think in your experience?
Should I really go just for a dual band N router? If, so, wich one would you recommend?
And how about the AirPort Extreme? Would that be a good option?

Thanks.

That's the problem -- what is out now in ac will quickly be obsolete, not future proof. Just like the very early N routers, these will not work with other ac stuff that comes out later. Moreover, if you wait for a more mature ac model the prices will have time to come down.

I would only go with dual band N if you are going to upgrade many or all of your adapters to dual band also. The best thing to do to extend range is to add an access point to your router -- any cheap router can be configured as an AP and will extend your range more than anything else you do.

My ISP router is very weak  
It's an Hitron BVW-3653. I think the best choice would be to shutdown it's wireless network and use it just as modem.

What wireless router would you recommend?
4 devices will connect to the wireless network. 3 support 802.11n and just one supprts only 802.11g (old laptop that is almost dying..)

Stay with inexpensive single band N then -- I like the DLink DIR-655. It has excellent range and 4 gigabit ports. I also use them as access points and they work very well.

In a year or so, 802.11ac will make more sense, but will still require all new adapters on your computers and devices.

You need to know that if you have a G device connect the network defaults to G speeds, and also only runs G speeds instead of N unless you use WPA2 with AES for your security.